Optimizing Heparin and Protamine Dosing During Cardiopulmonary Bypass Using Activated Clotting Time-Guided Protocols: A Single-Centre Prospective Randomized Controlled Trial.

OBJECTIVES

To evaluate whether an activated clotting time (ACT)-guided, formula-based anticoagulation strategy supported by viscoelastic coagulation monitoring (ROTEM) improves perioperative coagulation management and reduces bleeding compared with standard weight-based heparin dosing in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB).

METHODS

In this single-centre prospective, randomized controlled trial, 100 adults undergoing isolated CABG with CPB were allocated to ACT-guided management (n = 50) or standard care (n = 50). The ACT-guided group received individualized heparin and protamine dosing calculated using predefined ACT-based formulas targeting ACT ≥400 seconds. The control group received a fixed heparin bolus (300 IU/kg) with empirical protamine reversal. ROTEM was performed preoperatively, intraoperatively, and postoperatively. The primary end-point was total chest drain output at 24 hours. Secondary end-points included transfusion requirements, thrombotic events, platelet count variation, oxygenator performance, additional heparin or protamine use, ROTEM-derived parameters, and perioperative clinical outcomes.

RESULTS

The ACT-guided group had lower 24-hour chest drain bleeding and reduced total exposure to heparin and protamine. Intraoperative ACT values were more consistently within target range, with fewer supplemental heparin doses required. ROTEM demonstrated shorter clotting times and improved clot firmness, indicating reduced postoperative hypocoagulability. Platelet decline during CPB was attenuated. Transfusion rates (28% vs 52%, P = .01) and total allogeneic units transfused (0.6 ± 1.0 vs 1.4 ± 1.6, P = .003) were significantly lower, with no observed increase in thrombotic events.

CONCLUSIONS

Activated clotting time-guided, formula-based anticoagulation supported by ROTEM was associated with more favourable coagulation parameters and reduced bleeding without evidence of increased thrombotic complications within the limitations of the study sample size. Larger prospective studies are warranted to confirm these findings.